Last year Ristobar, owned by pastry king Gary Rulli, was a new addition to the Top 100 Bay Area Restaurants, thanks to the cooking of Angelo Auriana. However, Auriana left last spring and the cooking stagnated while Rulli tried to find a new chef.

While Auriana was a master, having worked at Valentino in Santa Monica in its heyday, the new chef, Michele Belotti, is a 25-year-old rising star who comes directly from Bergamo, Italy. He most recently cooked at the Michelin-starred Da Guido in Piemonte, and before that was chef de partie at Restaurant Frosio.

Belotti's menu is now in place, and a recent visit shows that he's definitely a chef to watch.

He's included some classics, such as agnolotti di Lidia ($18) stuffed with veal, pork, escarole and spinach in a veal reduction. I was about to order that dish, but asked our helpful waiter about the casoncelli ($18), a Lombardian-style pasta filled with prosciutto, pork, sage butter and dices of crisp pancetta, and he encouraged me to try it.

The dish showed Belotti's skills. Unlike American-bred chefs, he barely moistens his pasta with the sauce; it glistens on the pasta but barely pools in the bottom of the bowl. That's also the case with the paccheri ($16), a rustic tomato sauce with fennel-spiced pork sausage on fat tubes of what looked like super-size penne, properly a little chewy.

It made me want to explore every one of his pasta offerings, but I needed to try other things that would also show his mettle. That included a creamy potato soup ($8) with rosemary-scented croutons, and an arugula salad dressed with olive oil and Grana Padano cheese that forms a loose blanket over salty bresaola stuffed with goat cheese ($11).

Both were as you'd expect, with clean flavors and fresh ingredients. However, I did wonder about the burrata ($14) I saw on another table, which was served with wedges of tomatoes that looked mealy and pink. Didn't seem too seasonal to me.

Belotti's large plates are less interesting than the pastas, but follow the same principles of restraint. A pan-roasted pork tenderloin ($23) has just a smattering of sauce and a small pile of sauteed hedgehog mushrooms, while fillets of branzino ($26) are served with a potato sauce with a scattering of pine nuts and olives.

Tomatoes aside, the purity of Belotti's offerings is perfectly attuned to Bay Area tastes and a nice foil to Rulli's pastry obsession - what other Italian restaurant has 10 desserts on the menu?

The kitchen was out of my first choice, the millefoglie ($8), a puff pastry layered with mascarpone rum cream and soft caramel, so the waiter suggested the bignolata ($8), an eclair-shaped cream puff filled with Emporio Rulli's hazelnut ice cream with whipped cream, chocolate sauce and toasted hazelnuts. It turned out to be a great substitute.

Other choices included the Orange and Black ($9), a glass with a warm chocolate budino topped with orange marmalade, mandarin oranges and mascarpone rum whipped cream; miniature cannoli ($6); and house-made tiramisu ($8).

These are a reminder of the restaurant's former life as a cafe. A few years ago Rulli changed concepts and remodeled, but the place still has the feel of an elegant pastry shop, what with the whimsical frescos on the walls and ceiling, centered by an impressive Venetian glass chandelier. It's at once elegant and casual.

Service has also improved since my last visit, so it seems as if after a summer and fall lull, Ristobar is working its way back. It's not fully there yet, but as Belotti becomes acclimated he could become the new Italian darling of San Francisco.

Prices are based on main courses. When entrees fall between these categories, the prices of appetizers help determine the dollar ratings. Chronicle critics make every attempt to remain anonymous. All meals are paid for by The Chronicle. Star ratings are based on a minimum of three visits. Ratings are updated continually based on at least one revisit.